The present invention relates generally to a connector for structurally joining two or more structural elements, and particularly to a connector from a single casting that eliminates the use of weldments, which may or may not be subjected to fatigue-type loadings.
The prior art for providing the transfer of moment forces between a horizontally mounted tubular arm and a vertical tubular pole is through the use of weldments. Traditionally, simple mast-and-arm, post-and-arm, cantilevered service poles, traffic light poles and other similarly designed structures have used tubular members and attached the members by means of welded flange plates and/or welded splice plates and/or connection plates. These jointed structures are usually designed so as to be intentionally stronger than the individually attached structural members. They are designed to carry dead load and moment forces, and load shears and torsion loads (due, for example, to wind loading) about the vertical axis of the pole.
Weldments are subject to fatigue stresses. Recent structural failures and the resulting research has identified weldment fatigue failure as the primary cause of these structural failures. One result from the findings is a rewrite of the AASHTO (American Association of State Highway and Transportation Officials) Design Code involving a shift in critical design load consideration from base-metal requirements to that of weldment placement and quantity. The areas that are fatigue stress critical are the toe of the weld connecting the arm tube to the arm plate, the gusset plate weld between the pole plate and the pole tube, and the base plate weld to the vertical tube.
The present invention provides means and methods for joining two or more structural members without the use of weldments. The present invention provides a structural member without suffering the fatigue-load weakness of the prior art joint designs while still able to transfer intended design loads.
It is an object of the present invention to provide a connector to connect one structural member to another without the use of weldments.
It is another object of the present invention to provide a connector made from a single piece casting to connect one structural member to another without the use of weldments.
In summary, the present invention provides a structural connector for connecting a horizontal member to a vertical member, comprising an integral body from a single casting having a vertically oriented first sleeve portion and a horizontally oriented second sleeve portion. The first sleeve portion is integral with the second sleeve portion. The first sleeve portion has a tapered bore adapted to be slip fit around a tapered outside surface of the vertical member. The second sleeve has an outside diameter adapted to be slip fit within an interior bore of the horizontal member.
The present invention also provides a structural connector for securing the vertical member to a fixed base, comprising an integral body from a single casting. The body includes a vertically oriented sleeve portion and a flange portion oriented transversely to the sleeve portion. The sleeve portion and the flange portion are integral to one another. The sleeve portion includes an outside tapered surface adapted to slip fit inside a tapered bore of the vertical member.
These and other objects of the present invention will become apparent from the following detailed description.